Another example: American Psycho as a movie, is much, much better than the book. But by and large, books can do more with imagination than film can do with a screen.

Wow, you think so? You must not be a Bret Easton Ellis fan because I thought the book was far, far superior to the movie. Not even close. No way to portray all the stuff Ellis had going through Patrick Bateman's demented mind in the movie.